HFD Hazardous Materials unit wraps up the scene at the Mickey Leland Federal Building where a floor was evacuated and the rest of the floors were told to shelter in place after an oil substance was found in the Federal Building on Monday, May 20, 2013, in Houston.

Photo: Mayra Beltran

HFD Hazardous Materials unit wraps up the scene at the Mickey...

Image 2 of 4

Employees walk out of the Mickey Leland Federal Building where a floor was evacuated and the rest of the floors were told to shelter in place after an oil substance was found in the Federal Building on Monday, May 20, 2013, in Houston.

Photo: Mayra Beltran

Employees walk out of the Mickey Leland Federal Building where a...

Image 3 of 4

HFD Hazardous Materials unit wraps up the scene at the Mickey Leland Federal Building where a floor was evacuated and the rest of the floors were told to shelter in place after an oil substance was found in the Federal Building on Monday, May 20, 2013, in Houston.

Photo: Mayra Beltran

HFD Hazardous Materials unit wraps up the scene at the Mickey...

Image 4 of 4

HFD Hazardous Materials unit wraps up the scene at the Mickey Leland Federal Building where a floor was evacuated and the rest of the floors were told to shelter in place after an oil substance was found in the Federal Building on Monday, May 20, 2013, in Houston.

A suspicious package prompted a shelter-in-lace order Monday at the downtown Houston federal building.

A package was delivered about 3:30 p.m. to the 8th floor at the Mickey Leland federal building, 1919 Smith.

Workers noted an oily substance on the outside of the package and called authorities, officials said.

About five or six people who came into direct contact with the package were kept together in a secure room inside the building while the remaining federal workers were told to remain in their offices, officials said.

"They didn't tell us anything," a federal employee who declined to identify herself later said.

A Houston Fire Department hazardous materials team examined the package. They determined the oily substance wasn't hazardous but had the potential for causing irritation, officials said.

The people who were in contact with the oily substance were checked out but none were hospitalized. The package was turned over to investigators, officials said.

No further information about the package or the substance was immediately available.

The shelter-in-place, initially reported by fire department officials as an evacuation, was lifted about two hours later.